Q: "How can I restore the proper capitalization of my record IDs?"

A: Salesforce's 18-character record IDs are not truly case-insensitive (try it for yourself! Change the capitalization of an 18-character ID in a URL and see what happens).

I've added a new function to http://tinyurl.com/FieldUtilities that makes it possible to restore an 18-character ID's proper capitalization; once you've navigated to the link,

1. click "File | Make a Copy..." then
2. click the "Repair Broken 18-Char IDs" tab.

You can copy & paste any 18-character ID, with any capitalization, into a cell in column A and its proper capitalization will be returned in column C.

Feedback welcome!